The general information below is
intended as a general guide and should not be taken as
current legislation regarding specification and regulations
for compliance for Building control. The information was
extracted on 8th June 2008 from The Fire Safety
Advice Centre . Please refer to their web site
and seek advice from your local building control officer
regarding new updated information and new regulations that
Buildings are compartmented to delay the spread of fire
from one area to another. The compartments are usually linked
by doors to allow for passage of ‘traffic’ around
the building. Door sets have two important functions in a
fire, when closed they form a barrier to fire spread and
when open they provide a means of escape.
A well designed timber fire door will delay the spread of
fire and smoke without causing too much hindrance to the
movement of people and goods. Different parts of a building
may be separated from each other, into compartments of a
fire-resisting construction. Any openings leading from them
will have fire doors to maintain an effective fire barrier
and should prevent excessive transmission of products of
combustion which can interfere with the safe use of escape
routes. Every fire door is therefore required to act as a
barrier to the passage of smoke and fire to varying degrees
dependent upon its location in a building and the fire hazard
associated with the building. Consequently the functions
of a fire doors is, to provide adequate resistance to the
passage of smoke and other combustion products during the
early stages of a fire. Secondly to provide a barrier to
a well-developed fire without permitting fire and excessive
quantities of smoke to pass. Some doors may be required to
fulfil only the first function as they may not be subjected
to the full severity of a fire because of their location;
others may have the main aim of resisting fire penetration
as indicated by the second function. Some may have to meet
both requirements. At present, fire doors are specified as
smoke-stop doors when required to fulfil the first function
and fire-check and fire-resisting doors to fulfil the second.
Specifications of timber fire doors
The performance of timber doors is judged by subjecting
them to the standard test procedure specified in BS 476 :
Part 22: 1987 or BS EN 1634-1: 2000. Tests are made on complete
door assemblies, the door and frame with all the necessary
hardware. It is then fixed in a wall representing its use
in practice. By testing a door in one type of frame and using
it in another, no guarantee can be given of its behaviour
under fire conditions.
The test procedure is fully described in the Standard and
consists of exposing one face of the door to heat condition
expected in a fire whilst observing the door for stability
and integrity. The Standard requires the tests to be carried
out with the upper part of the door under a small positive
pressure, to simulate the conditions likely to occur in a
fire. It also provides an objective method of establishing
the loss of integrity of a door by the use of a combustible
fibrous pad on the un exposed side of the door and see when
it ignites. A door should be tested from each side to establish
its performance with either face exposed to fire conditions,
consequently requires two specimens.
It is reasonable assumed all fire doors and frames manufactured
to the same specification as the two specimen doors and frames
will achieve the same fire resisting properties.
Over the last few years a technique has been developed for
minimising the susceptibility of door edges to early penetration
by fire. It consists of applying intumescent strip to the
edges so that a rise in temperature will cause the material
to swell and close the gaps. Intumescent paints have been
used but the most successful and reliable technique is the
intumescent strip, about 4 mm thick by 10 mm wide, cut into
a groove in the door or the frame edge. As soon as the temperature
in the vicinity of the strips exceeds 200 degrees C, usually
about 10-15 minutes after the start of a fire, the strip
swells and seals the gaps. One strip is adequate for a half
hour fire door and for the increased protection needed with
one-hour doors, two of these strips will be necessary. The
intumescent material is soft and cellular in structure and
will not prevent deformation of the door.
There are fire resisting doors that are able to resist the
passage of fire for more than 30/60 minutes but these are
more likely to be used for the protection of property than
for means of escape from fire.
|Fire check and fire resisting
doors - Door type
 Integrity Failure is deemed to occur
when cracks or other openings exist through which flames
or hot gases can pass or when flaming occurs on the unexposed
 Stability Failure is deemed to occur
when collapse of the specimen takes place.
Identifying Fire Doors
Identifying fire doors is very difficult, however responsible
door manufacturers label their doors. This will identify
the manufacturer, the date of manufacture and the design
fire rating of the door type. They may fit a colour coded
plug instead of, or in addition to, the label. Identification
labels are usually fitted on the top or hanging edge of the
door and plugs in the long edges. For Hospitals, fire doors
display a disc at the top of each face of the door showing
the design fire performance see HTM58. Identification marks
are sometimes removed during installation, or adjustment
of the assembly and may have been painted over.
All dedicated fire doors providing a half hour or greater
performance will be fitted with intumescent seals. These
may be encased in a PVC sheath, of any colour, which may
also hold a blade or brush seal for smoke sealing purposes.
These seals are fitted in the door leaf edges or the frame
to seal the head and long edges of the assembly. A door may
be fitted with a concealed intumescent system where the long
edge sealing is housed under lippings. Intumescent seals
will be visible at the head of the door. Intumescent seals
expand under heating to seal the gaps between the door leaf
and the frame and at the meeting stiles of pairs of doors.
Doorsets using 44mm thick doors fitted with 10-15mm wide
intumescent seals are likely to be FD3O doorsets. When used
with 54mm thick doors using at least 20mm width of intumescent
seal, fitted as one or two strips, the design performance
for this doorset is likely to be FD6O. Doorsets with a rating
in excess of FD6O are rarely used on escape routes or to
protect people but may be found where property protection
is important e.g. data storage areas where documents cannot
be removed in the event of fire. Some of these doors have
the appearance of timber, but may be constructed with a mineral
core. Expert assistance may be required to identify such
You may have documentation that is supplied with the fire
door giving you all the necessary information. Unfortunately
there is no standard method of identifying fire doors other
than insisting on written proof that a fire door meets all
the necessary standards, for example a test certificate.
British Woodworking Federation is another organisation that
provides fire door ratings and the following is their system.
Fire ratings for fire door assemblies are given in minutes
and prefixed by the letters 'FD' i.e. FD 30 equates to a
30 minute fire door or doorset. The most commonly specified
integrity levels are:
- FD30 - 30 minutes (Half Hour)
- FD60 - 60 minutes (One Hour)
Intumescent Fire Seals
Intumescent fire seals and cold smoke seals should be fitted
to the back edge, stile and head of the fire resisting door
Fire Resisting Glazing
Ordinary glass cracks when exposed to heat and is liable
to fall out fairly early in a fire. Safety glass can withstand
exposure to the heating condition in a fire test for at least
30 minutes before it reaches a temperature high enough to
soften it. The main reason for this is that nearly 50 per
cent of the incident heat is transmitted through the glass
The size of the glass and the method of its retention are
important factors which influence its integrity. As the temperature
approaches the softening point a large sheet will tend to
collapse earlier than a smaller one. On the unexposed face,
beading retaining the glass is subjected to radiant and conducted
heat through the glass and to convection currents at the
top of the pane. This can raise the temperature sufficiently
to ignite timber beading after about 20 minutes. To delay
the ignition of beading to 30 minutes it is necessary to
provide protection by impregnation of a surface coating or
a surface covering of non-combustible material.
For longer periods of fire protection, an improved retention
system for the glazing is needed, so far only non-combustible
glazing sub-frames have been shown to be satisfactory. The
glass panel should be small and the method of fixing it should
ensure that no direct path can be created for the transference
of hot gases.
Years ago it was accepted practice to improve the performance
of an existing door to a half-hour fire-check or fire-resisting
standard, although in some cases it was more economical to
replace the door rather than alter it. The doors were usually
panel type or a light core flush type about 35 mm thick:
they require a facing on each side with a non combustible
board. This non combustible board quite often contained asbestos
which was acceptable to use then but not acceptable now.
There was no advice on improving the performance of existing
doors to a one-hour standard.
Consequently it may be necessary to replace damaged door
leaves or doorsets and in some cases, to install additional
fire rated doorsets. It is now the accepted practice to fit
new fire resisting doorsets preferably to upgrading them.
There are ASDMA members specialise in the manufacture of
bespoke performance doors and doorsets to suit customer defined
requirements. Associate members can supply many of the doorset
related materials and components. For further information
please refer to the ASDMA website.
Maintenance of Fire Doors
Fire doors are engineered products that provide life and
property saving functions in the event of fire. It is important
that they are regularly inspected and maintained to permit
them to perform at their best on the one and only occasion
when they are called upon so to do.
Doorsets fitted with hold open devices or swing free type
closer should be closed daily, particularly overnight when
there is likely to be low building occupancy. For busy 24/7
buildings (e.g. hospitals) fire doors should be closed at
least weekly. All fire doors should close effectively from
any angle of opening using only the door closer.
There are a number of reasons why doors may fail to close
- Check that there are no foreign bodies or other objects
obstructing the door.
- Check that any smoke seals are correctly fitted and are
- Check the latch, if fitted to ensure correct operation
and that it is suitably lubricated.
- Only as a last resort should the closing device be adjusted,
but this must be carried out carefully to ensure that the
doors can be opened without undue force.
Intumescent seals should be checked regularly, at intervals
not greater than 6 months, and damaged or missing seals replaced.
To maintain the design performance potential, replacement
seals should be of the same brand, size and type as the original.
However, any intumescent seal of the same size as the original
is better than none.
Mechanical items such as hinges, locks, latches, closer,
floor springs etc are likely to wear over time. Maintenance
provisions should comply with the hardware suppliers’ recommendations
where these are known. Otherwise, locks and latches may require
occasional light lubrication. Some hinges use self lubricating
bearings that will not need additional lubrication.
Where it is necessary to replace worn hardware on a fire
door, the essential items listed above should be replaced
with products to the same specification as the original where
possible. Otherwise hinges, latches, locks, flush bolts,
closer and other items of load bearing or securing hardware
should be of the same type and size as the original items
and should have been proven for use in timber fire rated
doorsets of the required performance. Hardware that has been
successfully tested in metal doorsets may not be suitable
for use with timber doorsets.
Redundant hardware should be carefully removed. Intumescent
gaskets may have been used under hinge blades; lock/latch
for end plates and strike plates, with some closer fittings
and in flush bolt recesses. These gaskets should be replaced
if possible with gaskets of the same material. Otherwise
they should be retained and reused with the new fittings
if they are undamaged. Intumescent gaskets or mastics used
for these applications are usually the low pressure type.
The following is a list of documents relevant to timber
BS 476: - 20: 1987 Fire tests on building materials and
structures. Methods for determination of the
fire resistance of elements of construction (general principles)
BS 476 - 22: 1987 Fire tests on building materials and structures.
Methods for determination of the
fire resistance of non-loadbearing elements of construction
BS 476: - 23: 1987 Fire tests on building materials and structures.
Methods for the determination of the contribution of components
to the fire resistance of a structure
BS 476: - 31.1: 1983 Fire tests on building materials and
structures. Method of measuring smoke penetration through
doorset and shutter assemblies – method of measurement
under ambient temperature conditions.
BS 8214:1990 Code of practice for fire door assemblies with
BS EN 1634-1: 2000. which is an alternative for BS 476 -